1. Field of the Invention
The present invention generally relates to sensing devices and, in particular, to such devices which use a floatation means for supporting a sensing element in proximity to the surface of a liquid.
2. Statement of the Prior Art
Sensing devices are often required to operate in hazardous environments. One very common hazardous environment for a wide variety of sensors is that of exposure to chemical agents which may either be corrosive in nature or be of a type which otherwise inteferes with the normal operation of the sensing device. One such hazardous environment which has been found to exist is in the area of detecting hydrocarbon containing substances in ground water. It has been found that various chemical compositions present in ground water from both natural and man made sources are corrosive or otherwise interfere with the sensing elements employed. To insure the long term reliability of the operation of such sensing elements, it is necessary to avoid the disadvantageous effects on the sensors used of the chemical compositions present in ground water.